Tesla founder and CEO Elon Musk used Twitter to taunt investors who have bet against his company, even though his previous Twitter comments have spurred a government investigation and shareholder lawsuits.

Mr Musk's attitude toward short sellers could be relevant, securities law experts have said. Mr Musk's tweet about taking Tesla private sent the stock soaring 11 percent Tuesday and cost short sellers roughly $US1 billion ($1.36 billion), according to some estimates.

If his motive for the tweet "was frustration with short sellers, then that could be a case of market manipulation," John Coffee Jr, a Columbia University law professor and corporate-governance expert, said.

Mr Musk mocked short investors in a series of tweets, suggesting his antipathy toward them had not dimmed.